For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningWaterleak Test Preparation
GM vehicles are designed to operate under normal environmental
conditions.
The design criteria for sealing materials and components takes into
consideration the sealing forces required to withstand the natural
elements. These specifications cannot take into consideration any artificial ...
Removal Procedure
Warning: Refer to Approved Equipment for Collision Repair Warning in the
Preface section.
Warning: Refer to Glass and Sheet Metal Handling Warning in the Preface section.
Disable the SIR System. Refer to SIR Disabling and Enabling.
Disconnect the negative battery cable. Refer to Bat ...
Tire Designations
Tire Size
The following is an example of a typical passenger vehicle tire size.
(1) Passenger (P-Metric) Tire: The United States version of a metric tire
sizing system. The letter P as the first character in the tire size means a passenger
vehicle tire engineered to standards set by the U.S. ...